Centerline two piece wheel and brake assembly

ABSTRACT

A dirigible wheel of an automotive vehicle has its steering axis on the vertical center line of the wheel, and a brake disc is supported with annular braking surfaces in vertical planes adjacent to the center line and are engaged by caliper type brake shoes.

BACKGROUND, SUMMARY, AND OBJECTS OF THE INVENTION

It is desirable to provide automotive vehicles with disc type brakeswhich comprise a flat disc-like rotor attached to the vehicle wheel andhaving a pair of hydraulic, air or vacuum actuated pistons which clamp asegment of the rotor thereto for applying a braking action to the wheel.Difficulties have been encountered with brakes of this type when appliedto the dirigible wheels of vehicles because out of balance conditions ofthe wheels cause vibrations of the rotors and the brake shoe mechanismsresulting in noise and deterioration of the hydraulic shoe actuatingmechanism.

The present application discloses a centerline steering wheel assemblyincluding a two-piece wheel and a disc brake. The brake rotor isattached to both parts of the wheel. This not only provides a morestable and reliable braking system but also offers a simplified meansfor changing tires. The wheel is fixed to a spindle rotatable in a hub.The speedometer drive gear assembly is directly connected to a rotatingspindle.

An object of the invention is to provide a new and improved dirigiblewheel and disc type brake mechanism for all surface vehicles, as forexample, passenger automobiles, trucks, buses, tractors or aircraftlanding gear, in which the steering axis of the wheel lies in the planeof the disc brake rotor on the wheel.

Another object is to provide a two-piece vehicle wheel and disc typebrake mechanism.

A further object is to provide a vehicle wheel mounted on a spindlewhich is rotatable in a hub, and a speedometer drive gear assemblyattached to the rotating spindle to rotate a speedometer shaft.

A still further object is to provide an improved ball joint assembly formounting a centerline steering wheel assembly to the upper and lowersupport arms of a surface vehicle.

Orher objects, features and advantages of the invention will be readilyapparent from the following description of a preferred embodimentthereof, taken in conjunction with the accompanying drawing, althoughvariations and modifications may be effected without departing from thespirit and scope of the novel concepts of the disclosure.

DESCRIPTION OF THE DRAWING

FIG. 1 is a rear elevational view of a front wheel assembly of a surfacevehicle, with the wheel being shown in section, the section being takenon a vertical plane thru the center of the wheel and transverselythereof;

FIG. 2 is an inside elevational view of the opposite, or left hand wheelassembly with the wheel in section;

FIG. 3 is an elevational view similar to FIG. 1 but with the hub,spindle, and yoke ends partly in section along Y--Y, FIG. 2, and thewheel and caliper housing in outline;

FIG. 4 is a detail of the upper trunnion pin anchor swivel stud;

FIG. 5 is a bottom view of the trunnion pin shown in FIG. 4;

FIG. 6 is a detail, partly in section, of the lower tapered trunnionpin;

FIG. 7 is a bottom view of the trunnion pin shown in FIG. 6;

FIG. 8 is a plan view of the ends of the yoke arms which are locatedabove and below the hub;

FIG. 9 is a view, partly in section, along line X--X of FIG. 1, showingthe front wheel speedometer drive gear assembly;

FIG. 10 is a sectional view of the centerline steering lower ball jointassembly structure;

FIG. 11 is a bottom view of the mounting structure of a ball jointassembly, with a bushing shown in section;

FIG. 12 is a view of an alternate form of yoke.

FIG. 13 is a view similar to FIG. 1 but showing a drum type brake systemand the alternate form of yoke shown in FIG. 12.

DESCRIPTION OF PREFERRED EMBODIMENT OF THE INVENTION

In the preferred embodiment of the invention illustrated in FIGS. 1-13 Ihave shown a two-piece dirigible wheel 1. This is one of the two frontwheels of a surface vehicle, not shown, and it is to be understood thatthe other wheel is identical in construction to the wheel 1, to avoidrepetition, the other wheel is shown only in FIG. 2. Wheel 1 comprisesinner tire rim half 2 and outer tire rim half 3. Wheel spider 4 issecured to the outer tire rim, as for example, by welding, and has oneor more openings 5 for both ventilation and access to the inside. RubberO-ring seal 6 is located in an annular groove 2b in the inner tire rimhalf. This groove is located at the inner edge of the outer tire rimhalf, which has an annular chamfer to fit around and over the O-ring inorder to compress the O-ring seal and form an air tight seal for thewheel. Inwardly directed annular mating flanges 6 are located at therespective ends of inner tire rim half 2 and spider 4. Threaded rotorstuds 8 and rotor stud nuts 9 secure the two halves of the wheeltogether. If desired, locating dowel pins, not shown, may be used forcentering the flanges with respect to each other. A tool may be insertedthrough openings 5 to remove the stud nuts. The annular mating flangesalso provide a significant increase in the strength factor needed on thevertical and horizontal centerlines of the wheel to withstand the severewheel and brake torque forces.

FIGS. 1 and 2 show how the brake rotor disc 10 has an annular attachingflange 10a and is attached to the wheel by rotor studs 8 and nuts 9. Thevertical planes of the wheel and of the rotor disc, which areequidistant from and parallel to the planes of the wheel rims 2a, 3a,are coincident. A brake caliper assembly completes the brake system.Caliper housing 11 provides a housing or chamber for a hydraulic pistonon one or both sides of brake rotor disc 10. As shown in full lines inFIG. 1 hydraulic pressure is applied to only one side of brake rotordisc 10. Fixed opposing bracket 12, along with the hydraulic piston,permits braking pressure to be applied to both sides of the rotor disc.One or more brake surface pads or shoes 14 are held in a self-floatingcavity provided for in the caliper housing. Opposing surface frictionalpad 14 is maintained in a self-floating condition in bracket 12. Thedotted lines in FIG. 1 opposite caliper housing 11 merely indicate thateither a "left hand" or a "right hand" construction may be used. Theconstruction is essentially the same and in the interest of clarity thisshowing has been used. Likewise, a hydraulic piston and caliper housingmay be used on both sides, thereby substituting a hydraulic piston foran opposing bracket.

In the centerline steering system the wheel and spindle 24 are heldtogether and the spindle rotates inside a hub 15. In steering thevehicle the wheel, brake rotor, spindle and hub turn together as a unitabout a vertical axis which is coincident with the vertical center lineof the wheel and brake rotor disc. This center line is indicated bybroken line CL. The hub is supported by upper trunnion pin 16 and lowertrunnion pin 17. The trunnion pins are threaded into upper and lowerarms 18, 19 of a yoke member 20. In FIG. 12 an alternate yoke member 20ais shown. The yoke member 20 is connected to conventional upper andlower support arms 21, 22 of a surface vehicle, not shown, by upper andlower ball studs 23, 23.

Spindle 24 has a circular central boss 25 projecting from the hub and anannular flange 26 extending radially from the boss. The wheel 1 ismounted by securing spider 4 on annular flange 26 by means of spindlestuds 27 and taper nuts 28 or wheel bolts. The spindle is supported forrotation in the hub 15 on tapered wheel bearings 29, 30. The lowercavity inside the hub provides oil sump 31 to lubricate the wheelbearings. A spring loaded mechanical oil seal 32 is pressed into theundercut surface in annular flange 26 and overlies the machined neckportion 35 of the hub. Hubcap 33 closes the opposite, or inner, end ofthe hub. Inspection glass 34 in the hubcap provides a visual check ofthe oil level inside the hub. The hubcap also has threaded element 36secured to it in alignment with the spindle. The purpose of element 36will be described later. The hubcap may be secured to the hub by bolts37 and sealed with gasket 38. A breather plug 39 (FIG. 2) is threaded tothe mid section of the hub and serves as an internal pressure reliefvalve and oil filler plug.

Since the hub turns only when vehicle steering takes place it issupported by upper and lower trunnion pins 16, 17 which are threadedinto the upper and lower yoke arms 18, 19 respectively. FIG. 8 shows howthe ends of the yoke arms are slotted at 40 to provide an opening for apinch type trunnion pin lock by means of socket head lock bolt 31.Threads 42 in the yoke arms receive the respective threaded trunnionpins, FIG. 4 and FIG. 6. The slotted end 40 provides a relief openingengagement surrounding both trunnion pins for easy assembly anddisassembly. This slotted or split type yoke is particularly useful intrucks and other heavy vehicles. FIG. 3 shows the trunnion pins nestedin their respective bushings. The shapes of the bushings and trunnionpins are important to the proper functioning of the device. The uppertrunnion pin cooperates with two separate load bearing members, namelythe hub 15 and upper yoke arm 18. Additionally as shown in FIGS. 3 and4, the upper portion 16a of trunnion pin 16 acts as a swivel stud tosupport brake caliper housing 11, while the lower semi-spherical ballend supports the full static and dynamic load forces applied to bushing43 recessed in the hub. Hexagonal collar 16b is a means of turning thetrunnion pin to adjust clearance between 16 and bushing 43 and has anupper flat surface which may support the brake caliper housing. Thelower trunnion pin 17 is tapered and fits up into its bushing 44. Thetaper is important to align opposing bearing surfaces to stabilize thehub. The taper end is self-aligning and shares the greater part oflateral thrust forces, but it also compensates for any wear clearanceswhich may occur on the upper companion pin 16 or bushing 43. Flexiblemechanical seals 45 prevent outside contamination into the upper andlower trunnion pin and bushing areas. FIGS. 6 and 7 show hexagonalrecess 17a for receiving a socket wrench to adjust trunnion pin 17 tobushing 44. The trunnion pins are treated to be permanently lubricated.Space between yoke arm 19 (FIG. 1) and rotor 10 is needed in order tofit caliper 11 over pin 16a.

The trunnion construction described above permits the steering of thevehicle by a direct connection of the vehicle steering rod or system(not shown) with the hub. Steering arm bracket 46 is attached to theside of the hub, as with bolts 47. Steering arm ball 48 has a studportion 49 extending through a hole in a boss 50 at the end of the armbracket. The stud is anchored by castellated lock nut 80 and cotter pin81.

A caliper and bracket assembly, comprising supports 52, is secured to orintegral with caliper housing 11 and bracket 12. Supports 52 are securedto the hub as by bolts 53. These supports, together with the swivel studportion 16a of upper trunnion pin 16, which fits into bushing 13, serveto additionally anchor the caliper housing 11 and bracket 12 to hub 15.The bushing 13 is a serivceable or replacement bushing required forbearing the caliper housing. The continued swiveling and brake torqueaction will require this bushing to be replaced on periodic brakerebuild intervals. It may be made of any suitable material, as forexample, bronze or sintered metals. Thus the caliper portion of thebrake system and the vehicle steering system are both anchored to thehub. The wheel 1 and the brake motor are secured to the spindle. Theinner end of the spindle is secured for rotation inside the center ofthe hub by means of spindle nut 54 and spindle lock washer 55. The wheelis fitted with tire inflator valve 56.

The assembly and disassembly of the centerline tire and rim is simple,easy and safe. The two tire rim halves may be put together from theopposite sides of the tire. However, in the case of heavy trucks andbuses the conventional mounting of tires on wheels is cumbersome,hazardous and costly. The conventional tire bead safety lock ring mustbe properly seated against the outer rim radius to lock the tire beadoutside radius to the lock ring. If, during the tire inflation period,the bead, lock ring and rim surfaces are not closely engaged, the lockring, under incoming tire pressure, may blow the ring from the rim withintense velocity causing injury or possible death to anyone standingnearby. The centerline two-piece wheel eliminates the need to carry anextra spare wheel for a quick interchange. A spare tire is concealed ina small space thereby reducing the weight and space required for aconventional wheel-tire spare assembly. The two-piece wheel design isalso interchangeable with rear wheels. Recent transportation laws havebeen passed by Congress mandating safety highway improvements on alltypes of surface vehicles. Steering safety shares a significantimportance toward reducing highway accidents. This involves wheels,brakes and front end suspensions. It is recognized that two-piece wheelshave been commercially produced for the aircraft industry. But the wheeldisclosed herein is not in the same context, and with its brake rotordisc, it rotates together with a live spindle as part of the centerlinesteering system.

The wheel and brake system described thus far is applicable to surfacevehicles of all dimensions such as for example passenger vehicles, largetrucks, buses, aircraft landing gear and tractors. The ball studs 23, 23are particularly adapted to use with passenger vehicles, in part becauseof the universal design and structure of standard present day passengervehicles. Trucks and other large vehicles, because of the enormousweights they carry, often have front end suspension designs which aredifferent from those of passenger vehicles. FIG. 12 shows an alternateform of yoke construction wherein yoke 20a also has yoke arms 18, 19into which trunnion pins 16, 17 are threaded. But in this alternate formthe other end of the yoke is integrally or rigidly attached to thevehicle frame (not shown) rather than by ball studs 23, 23.

The centerline structure for connecting the yoke member 20 to theconventional upper and lower support arms 21, 22 of a surface vehicle isshown in FIGS. 1, 10 and 11. The upper ball joint assembly 57 and lowerball joint assembly 58 are similar and will be described together. FIG.10 applies to both. Upper ball joint yoke boss end 59 and lower balljoint yoke boss end 60 with their upper and lower ball studs 23, 23provide the basic connections for attaching the centerline wheel, brakeand hub assembly to the conventional upper and lower support arms of avehicle, which in turn are interconnected to the vehicle frame andspring suspension members. The axes of the upper ball stud and upperball joint yoke boss are vertical and coincident. The axes of the lowerball stud and lower ball joint yoke boss intersect the above mentionedupper axes. The inclined lower ball axes are essential in order to fitthe centerline construction herein described to the conventional vehiclesupport arms. Such conventional support arms result from the use of theusual kingpin construction and its need for camber and casteradjustment.

The centerline steering system does not itself require compound angularadjustments; however, the mounting structure disclosed herein isessential to fit the conventional support arm ends thereby providing aninexpensive changeover to the centerline system. Ball joint assemblies57, 58 are significantly different from what one might assume to betypical ball joints. The ball studs comprise a spherical segment or flatsided ball 61, whose flat sides 61a, 61a are equidistant from the centerof the sphere, and a tapered shank portion 62. The flat sides of thespherical segment prevent any rotational movement when seated in theflat sided cavity of lower bushing 63. Freedom of movement is limited toa vertical plane. The significance of this construction lies in therotational locking device which it provides when the centerline steeringstructure is mounted to the upper and lower support arms provided by thevehicle manufacturer. The conventional steering system requiresspherical ball joints constituting the hinged members for the wheels toswing into and out of turns. Since the centerline wheel pivot axis in onthe true centerline of the hub I have devised this method to provide aninexpensive conversion to the centerline structure.

It must be remembered that the flat sided ball (spherical segment)prevents turning of the yoke in a forward or backward direction but thecurved surface motion up and down in an arcd jounce motion for goodrideability and suspension floatation.

The lower bushing 63 is shown in section in FIG. 11 and the ball 61 andshank 62 are shown in full view. Lower bushing 63 has an annular flange64 which supports the bushing in lower hemispherical shell cage 65. Theshell cage is integral with flat plate 66. Above and in direct contactwith plate 66 is upper flat plate 67, which also has a hemisphericalshell cage 68 which is opposite shell cage 65. Upper bushing 69 has anannular flange 70. Bushing 69 is fitted to the inside of shell cage 68with annular flange 70 extending below plate 67. The bushing 69 andshell cage 68 are pressed into the surface of ball 61 aligning the flatsurfaces thereof. Lower hemispherical shell cage 65 contains 63, supportbushing 71, and tension spring 72. Shell cage 65, with its bushings andspring in position, is located over the ball and the two shell cagesheld together and secured to outer and inner snaplock 73 as for exampleby plug welding. Snaplock 74 provides an internal lock to prevent thebushing from rotating in the shell cage. A closure gap 75 locatedbetween annular bearing flanges 64 and 70 provides lip spacing whentension spring 72 applies pressure against support bushing 71.

The ball joint assembly is partially enclosed by a molded rubber sealingboot 76. The upper and lower shoulders surrounding the shank portion 62and overlying plate 67 and shaped to size.

Tapered shank 62 has a slot 77 wherein a lock pin 78 is driven toprevent any rotational movement in the yoke boss end. Any rotation atthis point or within the confines of the joint would affect theCenterline alignment.

The upper and lower yoke boss ends 59, 60 must be positioned to matchthe ball joint centerlines prescribed by the vehicle manufacturers.Caster shims may be used between plate 67 and support arm 22, if agreater degree of caster is required.

Upper and lower ball joints 57, 58 are identical in construction buttheir position extending upwardly or downwardly is entirely dependentupon the direction of load on the yoke boss ends. Different automobilemanufacturers have different constructions in this respect, as is wellknown in the art. However, the tension spring 72 location must always bemounted on the non-loaded ball socket half to compensate for wearoccurring on its companion half. Support bushing 71 may be enlarged toreplace tension spring 72 when it is located on the loaded side of theball. Castellated lock nut 80 is threaded on the end of shank portion 62to secure the ball joint assembly to its boss end. Cotter pin 81 isprovided to secure the lock nut.

The two-piece wheel construction with the brake rotor disc providesample spacing for the caliper connection to the hub with the upperportion of the trunnion pin 16 acting as a swivel stud. In light of theclearances provided it is now possible to increase the number of brakingpistons and pads required for heavier braking requirements without acostly modification as would be required in the conventional wheel anddisc brake assembly.

The centerline wheel and brake construction overcomes several problems;problems inherent in either the conventional disc or drum brake design;more specifically, problems relating to brake action time when inputpressure is applied to actuate braking members. The conventional systemcauses a twisting action on the axle and brake members after the brakesare applied. This in turn causes slow recovery after the brake isreleased. The reaction time or moment for said members to return to theoriginal shapes causes brake sluggishness or slow retardation. Theseproblems, for the most part, have been difficult to meet under thebraking standards set forth by the U.S. Department of Transportation,especially on heavy trucks and buses. Several new expedients have beendesigned to meet these standards; however, these devices have failed toeffectively solve the on-going problems.

It will be virtually impossible to solve the conventional steering andbrake problems because of the sprung mass loading forces hingedoutwardly from the conventional king-pin or ball joint pivot axes. Theultimate solution is based on may past experience in combination withthe centerline steering and brake construction.

The structure, herein disclosed, solves the reactionary brake problems-- which is an incontestable claim -- the axle wheel and brake alignmentplaces all parts immediately over a true vertical plane and forces areequally disposed over the wheel pivot axis. In addition, the brake rotordisc 10, with its attaching flange 10a secured to the annular matingflanges 7, 7 adds strength and rigidity to the wheel and thus increasedresponsiveness to the entire brake system.

Added to the many advantages described hereinabove for the centerlinehub, spindle and brake system is the ease with which a rotating spindleand hubcap may be modified to directly connect the rotating spindle toan inexpensive speedometer drive mechanism 51 for all surface vehicles.This is due to the fact that the centerline construction is based upon avehicle wheel spindle rotating in a hub. The details of the drive gearassembly are shown in FIG. 9.

Hubcap 33 is a mounting support member for the drive gear assembly sinceit is anchored to the hub by bolts 37, with a sealing gasket 38therebetween. Spindle nut 54 secures the spindle to the hub incooperation with tapered wheel bearings 29, 30. The input speedometerdrive shaft 82 is fixed to the spindle, preferably by being non-circularin cross section and mating with corresponding non-circular hole 83 inthe spindle. Bevel gear 84 is fixed to the end of shaft 82 and mesheswith bevel gear 85. Bevel gear 85 is fixed to the output shaft 86, whichmay be interconnected to a flexible speedometer drive cable, not shown,and thereby coupled to a speedometer dial located on the instrumentpanel inside the vehicle.

The drive gear housing 87 hermetically seals all internal components.Sealing swivel nut 88 overlies housing shank 89, and a snap ring 90 isinterposed, locking the swivel nut and housing shank. The snap ringprovides a bearing surface for the swivel nut as well as sealing theinternal parts from outside contamination.

The swivel nut 88 is threaded onto element 36 to a tight sealing fit,thereby mounting the complete assembly on the hubcap. Seal 91 includes awasher and is swaged into element 36. Spacer block 92 is pressed intothe inner housing cavity and provides a secondary bearing surface forinput shaft 82. Spacer 93 may be secured to the housing, as by a pin, toprovide further support for the gear and shaft. The output shaft 86 isintegral with gear 85 and has a non-circular hole 94 for coupling thespeedometer cable, not shown. Spacer block 95 is pressed into thehousing cavity to provide a bearing member supporting bevel gear 85 andoutput shaft 86.

The centerline spindle and speedometer gear train is very inexpensivecompared to the expensive complex gearing mechanism now commonly used onconventional steering and wheel mounted axles. Conventional designrequires a mounting plate attached to the inner surface of the wheel andtherein connected to a series of driving reduction gears overlyingcommon supporting members which are interconnected to a shaft extendingthrough a backing plate and inwardly connected to an adapter connectedto the flexible speedometer drive cable.

The centerline structure eliminates the need for numerous additionalparts required to provide the same 1 to 1 ratio required for aspeedometer reading in M.P.H. The centerline drive is compact andhermetically sealed. The gears, shafts and spacers are all treated to beself-lubricating. The output gear shaft is designed on a 90° angle toproject the flexible drive cable rearwardly toward the instrument panel.It is recognized that there will be a bending radius in the flexiblecable when the front wheel is turned in both directions. This radiusfalls within the tolerances set forth by the cable manufacturer.

The two-piece wheel, as stated hereinabove, is also advantageous for useon heavy vehicles such as trucks, buses and tractors. Because of theheavy loads involved it is sometimes desired to have the yoke memberdirectly anchored on the vehicle frame or vehicle axle. In suchconstruction the ball joints are eliminated as shown in FIGS. 12 and 13.

Since the two-piece wheel provides such ample space inside the wheel,and the mating flances 7, 7 are located at the central plane of thewheel and tire, it may also be used with a drum type brake system, asshown in FIG. 13.

Annular brake shoe drum 96 has one or more flanges 97. The flange 97 isfastened to mating flanges 7, 7 by threaded brake drum stud 98 and brakedrum stud nut 99. Brake shoes 100, 100 are supported by shoe guide pin104 on brake shoe anchor 101 which is secured to the hub or is integralwith the hub. Shoe guide pin 104 is held in place by C-washer 103 andspring washer 105. The brake shoe actuating mechanism is not shown. InFIG. 13 the steering arm bracket 102 extends upwardly rather thandownwardly, as illuminated in FIGS. 1 and 2, to show an alternativeconstruction which may be selected for use with some manufacturer'ssteering arm. The wheel is of two-piece construction similar to thatdescribed hereinabove.

I claim:
 1. A dirigible wheel assembly for a surface vehicle,comprising: a wheel member; a hub; a wheel spindle journalled in saidhub; means supporting said hub for turning movement about a steeringaxis lying in a plane normal to the axis of rotation of said spindle andcomprising a yoke member having parallel arms extending above and belowsaid hub, and bearing means between said arms and said hub and forming apivot for swinging said hub about said steering axis; said wheel membercomprising a tire rim and a spider attached to said spindle by anattaching member, and an inwardly directed annular flange on the innerperiphery of said wheel member; an annular brake rotor disc presentingannular brake shoe engaging surfaces lying in planes normal to the axisof rotation of said spindle; attaching means on said brake rotor discfor rigidly attaching the brake rotor disc to the inwardly directedannular flange, and a brake caliper and bracket assembly having a brakecaliper housing secured thereto, and at least one brake surface pad forselectively applying pressure against said brake shoe engaging surfaces,said hub having vertical surfaces on each side substantially parallel tothe axis of rotation of said wheel spindle, said brake caliper andbracket assembly having supports for said brake caliper housing onopposing sides of said brake caliper housing extending over said yokeand parallel to said axis of rotation of said wheel spindle and matingwith said hub surfaces, and securing means for securing said supports tosaid hub at the mating surfaces.
 2. A dirigible wheel assembly asrecited in claim 1 wherein the top of said yoke member has a trunnionpin, and the brake caliper and bracket assembly has a bushing fittingover said trunnion pin to form a swivel for further supporting saidbrake caliper and bracket assembly.
 3. A dirigible wheel assembly for asurface vehicle as recited in claim 1 wherein a steering arm bracket isattached to said hub for turning said hub and said wheel member aboutsaid steering axis.
 4. A dirigible wheel assembly as recited in claim 1wherein said wheel member comprises an inner rim half and an outer rimhalf, and said spider is secured to said outer rim half, inwardlydirected mating flanges at the outer end of the inner rim half and atthe inner end of the spider, respectively, and meeting each other in aplane normal to the axis of rotation of said spindle, means forreleasably connecting said mating flanges, and the attaching means onsaid brake rotor disc being releasably attached to said flanges.
 5. Adirigible wheel assembly as recited in claim 4 wherein the attachingmeans on said brake rotor comprises the means for releasably connectingsaid mating flanges.
 6. A dirigible wheel assembly as recited in claim 4wherein the spider has tool access openings in line with the means forreleasably connecting said mating flanges.
 7. A dirigible wheel assemblyas recited in claim 4 wherein said brake rotor disc, said brake caliperand bracket assembly, said hub and said wheel spindle are entirelyinside the wheel member within planes extending through the inner edgeof said inner rim half and the outer edge of said outer rim half.